BBC/Warner Home Video

In terms of cultural impact, Dr. Who is the British Star Trek and Star Wars put together. The BBC-TV series about a dapper two-hearted alien traveling through time and space in what looks from the outside like a blue police box, first went on the air in 1963 and ran continuously until 1989. Three years ago the BBC revived it and it's now bigger than ever. The new series retains much of the charm of the old — for instance, gnarly monsters who speak in impeccable British stage accents — but with better writing, acting and visual effects. It's among the most popular shows on British TV, winning most major awards, and has made the current Doctor — David Tennant — into the most bankable actor in England.

It's carried in the states on the Sci-Fi Channel (which got a huge ratings boost when it started) about six months after it runs in Britain. The 15 episodes end here in October, and then the DVD set comes out — which is by far, far the best way to see it. Though familiarity with the Doctor Who universe adds to the experience, it's more than possible to jump right in and enjoy the best science fiction series now on TV anywhere.

The third season (second for David Tennant) is as least as good as the excellent second season and the pretty damn good first season, and arguably better. Executive producer and writer Russell T. Davies orchestrates the season so that there are stand-alone episodes, some of which would be classics even without the Doctor (such as this season's "Blink"), and two-parters (like "Daleks in Manhattan," featuring the most famous series villains), but also with a season-long arc, seeded from the first episode and becoming apparent in the final ones. This year he's managed to drop what seems to be a one-time device into a stand-alone that becomes the key to the revival of another old nemesis (played, at least in part, by none other than the eminent Derek Jacobi.)

I think there are two keys to the new Doctor Who's success. First, many of the people who make the series now (including David Tennant) grew up with it as children, and while they've improved the show dramatically they're true to its traditions. And second, it remains a show made for children (it airs in the UK early Saturday evening). So it always has monsters and adventure, it's always a little scary, and it's eventually always positive.

But like other great children's entertainment — Bugs Bunny, Tom Corbett, Mathnet, Harry Potter, etc. — it uses that freedom to layer in more wit and meaning than adults would stand for. It deals with basic issues important to children — such belonging and difference, freedom and family, and in particular the basic issues of good and evil, godlike power and sacrifice — that would scare adults to death.

There's the same dash and humor as the classic series, but the characters and relationships continue to be developed. The Doctor's companion (usually female) is still a kind of stand-in for the audience point of view, but beginning with Billie Piper as Rose Tyler the first two years, and now with Freema Agyeman as Martha Jones (the first companion-of-color), she has a more active role, and there's more reality in the relationship.

The Doctor is more dimensional as well. Still charming, he is sometimes seen as a lonely, even vengeful god, struggling with impulses for justice or compassion. This season — and especially the final episode — is imaginative and powerful in this regard.

If you love extras, this DVD set is loaded. Besides the entire, uninterrupted episodes, there's also the DVD option of subtitles, so you can understand all that these fast-talking Brits are saying. And especially for in-house effects, the visuals are great. It's a lot of fun.